In context with the transition elements, which of the following statement is incorrect?

• Correct answer
  A

  In the highest oxidation states, the transition metals show basic character and form cationic complexes.
• B

  In the highest oxidation states of the first five transition element [Sc to Mn], all the 4s and 3d electrons are used for bonding.
• C

  Once the ${\mathrm{d}}^5$ configuration is exceeded, the tendency to involve all the 3d electrons in bonding decreases.
• D

  In addition to the normal oxidation states, the zero-oxidation state is also shown by these elements in complex.

Hence, the correct answer is option: 'A'.